- Astringent (clarifying agent made from persimmon tannin)
A flocculant (fining agent) used in the production of sake; made from persimmons. Varieties of astringent persimmon particularly rich in tannins are harvested while still green, crushed, and pressed, and the juice fermented for around a month. The shibu is then sterilized by heating, and aged for a number of months or years.
It is a reddish-brown or reddish-black liquid with pH 3-4, specific gravity of 1.02 to 1.04, 7-10% solids and 2-3% organic acids (of which 90% are volatile). About 5-6% of the tannin content is effective in the ori-sage process. Apart from use in sake ori-sage, it is also used as a clarifying agent in foodstuffs, in protein removal, as a wood coating, in tanning fishing nets, fabric dyeing, as a raw material for cosmetics and as a deodorant.